Resolved questions못& (르)러 가/오가

1)못해요 or 못 해요?with space or not?2)한국어책 or 한국어 책?with space?3)when using (으)러 가/오다, do we need to mention the place? as I have seen that for example:수업을 끝내고 밥을 먹으러 갔어요.If in that case,we don't know where to have meal so is ot correct?